This invention relates to cache control in I/O processing using cache areas of servers and storage systems.
In recent years, application of a nonvolatile memory, for example, a flash memory, to servers and shared storage apparatus is in progress. The non-volatile memory express (NVMe) is proposed as an I/O stack intended for the nonvolatile memory.
The NVMe is an I/O stack that reduces a CPU load imposed by I/O processing compared with existing I/O stacks in order to take advantage of a high speed property of the nonvolatile memory. Therefore, the speed of an application having the CPU load as a bottleneck can be increased by using the NVMe. It is expected that the NVMe is used more frequently from now on.
In the NVMe, extensions of commands issued during the I/O processing are proposed. Hint information is known as one of such extensions (refer “NVM Express revision 1.1b specification”, 6.7.1 Context Attribute). The hint information is information indicating how data to be accessed is used by the application.